In a Long Term Evolution (LTE) system, an evolved Node B (eNB) may receive data transmissions from user terminals or user equipments (UEs) and transmit one or more Hybrid Automatic Repeat Request (HARQ) indicators on Physical HARQ Indicator Channels (PHICHs). If a data transmission from a (UE) is successfully decoded, the eNB may set a HARQ indicator to acknowledgement (ACK). If a data transmission from a UE is not successfully decoded, the eNB may set a HARQ indicator to negative acknowledgment (NACK). The eNB may transmit the PHICHs in a Downlink (DL) channel to a UE. The UE may determine the HARQ indicator transmitted by the eNB.
In a typical HARQ process, if the UE determines that a HARQ indicator is a NACK, the UE may re-transmit the data. The UE may repeat this process until a HARQ indicator that represents an ACK is received or a maximum number of retransmissions is reached. Therefore, an erroneous determination of the HARQ indicator at the UE may affect the performance of the LTE system. If a NACK is mistakenly identified as an ACK, the UE may terminate the HARQ process prematurely and fail to deliver the data to the eNB. Conversely, if an ACK is mistakenly identified as a NACK, the UE may waste system resources by generating useless or unnecessary retransmissions and creating extra interferences.